If I recall from years back, the FDA approved the "label" on the pink top tube not the actual tube itself. It had boxes that dictated what to write where vs a single blank label.

Our specimen of choice is the large pink EDTA, as others have said, for the volume advantage and for easy specimen separation by processing staff. We do use the lavender if we have to share. No problems with either. We use capture technology and an Echo.

I disagree, what's wrong with using the purple tube?

The dilution factor of the liquid EDTA is not going to affect any blood bank testing.

It simple enough for phlebotomists to draw 2 purple top tubes if hematology and blood bank testing are both ordered and, if your lab requires the same level of patient identification and sample labeling as the blood bank does you can use the hematology sample in a pinch.

If you can show me data that indicates a difference in test results between the 2 tubes then some one should tell the FDA so they can force us to stop using the purple tubes. I'm fairly confident that no such data exists.

I am in agreement with John here, we routine use both the 3mL and 7mL tubes for transfusion testing. I have been using the Immucor Echo for two years now and manual gel testing prior to that. We have been utilizing the two tube types for the last nine years with no discernable difference.